(a) Field of the Invention
The present invention relates to a stackable material handling container having leg members permitting many containers in their closed or open condition, to be stacked one on top of each other.
(B) Description of Prior Art
More specifically, the present invention relates to a stackable material handling container having collapsible side walls which are collapsible on a bottom support wall, the container being provided with leg members permitting many of said material handling containers to be stacked one on top of the other with the collapsible side walls collapsed on the bottom wall.
Various types of collapsible material handling containers have been provided for shipping or storing material. A disadvantage of known types of containers is that when the side walls thereof are collapsed, a great many of these are not stackable one on top of the other for storage or shipping. With known containers, it is necessary to position two or three of such collapsed containers on top of the others and then tie them together with rigid strapping means. These containers are fairly heavy and are handled usually by fork lift trucks and often, with these prior art containers, they are damaged as they are not easily picked up by the fork lift truck due to their construction. Also, when these are stacked in a vehicle for shipping, it is very difficult to pile them up, as they are unstable in their packaged form due to the fact that their top surface is not uniform when the side walls are collapsed thereon. This makes them expensive to transport. Also, these are often damaged when positioned one on top of the other as there are no mating bearing surfaces providing clearance of the collapsed side walls with an adjacent container positioned thereover.
Still further disadvantages of the prior art containers are that they are heavy in construction because they comprise rigid steel channel members in the base thereof or the legs are formed from rigid channel members, thus making them difficult to manoeuver. Still further, the channel construction accumulates dirt or other unsanitary deposits therein and such containers cannot be used to support foodstuff unless they are cleaned each time they are utilized. Also, when foodstuff is carried by the contained particles of such foodstuff will accumulate in the channel members and rot, thus constituting an unsanitary container when in use.
A further disadvantage of known containers of the above type is that when the collapsed containers are strapped in bundles of two to four, it is very dangerous to handle them as the package is unstable and when the metal straps are removed, these can snap off in a whipping action sometimes causing injuries. Furthermore, with known type containers, it is difficult to stack them one on top of the other when the containers are in their open or erected position as there is no means to permit alignment of the containers one on top of the other. It is usually required to have a person guide the lift truck operator when a container is positioned on top of the others, particularly if the container stack exceeds eight feet in height. Further, the sequence of folding the walls onto the bottom support wall of the container is difficult and sometimes it is necessary to repeat the sequence a few times before each side wall is properly collapsed when on top of each other in a neat pile.